Use the following data to determine the AH° for the conversion of diamond into graphite: C(s,diamond) +0,(g) Co,(g) AH°= -395.4 kJ 200,(g) 2c0(g) +0,(g) AH°= 566.0 kJ 2C0(g) C(s.graphite) + CO,(g) AH°= -172.5 kJ C(s,diamond) AH° = →C(s,graphite) kJ

An industrial process for manufacturing sulfuric acid, H2SO4, uses hydrogen sulfide, H2S, from the purification of natural gas. In the first step of this process, the hydrogen sulfide is burned to obtain sulfur dioxide, SO2. 2H2S(g)+3O2(g)2H2O(l)+2SO2(g);H=1124kJ The density of sulfur dioxide at 25C and 1.00 atm is 2.62 g/L, and the molar heat capacity is 30.2 J/(mol C). (a) How much heat would be evolved in producing 1.00 L of SO2 at 25C and 1.00 atm? (b) Suppose heat from this reaction is used to heat 1.00 L of the SO2 from 25C to 500C for its use in the next step of the process. What percentage of the heat evolved is required for this?

In 2010, 3.30109 gallons of gasoline were consumed in the United States. The following assumptions can be made: • Gasoline is mainly n-octane, C8H18(d=0.7028g/mL). • Burning one mole of n-octane in oxygen releases 5564.2 kJ of heat. • The heat capacity C of the surface region of the earth is 2.61023 J/K. What is the increase in temperature of the surface region of the earth due to gasoline consumption in the United States?

The formation of aluminum oxide from its elements is highly exothermic. If 2.70 g Al metal is burned in pure O2 to give A12O3, calculate how much thermal energy is evolved in the process (at constant pressure).

Dissolving 6.00 g CaCl2 in 300 mL of water causes the temperature of the solution to increase by 3.43 C. Assume that the specific heat of the solution is 4.18 J/g K and its mass is 306 g. (a) Calculate the enthalpy change when the CaCl2 dissolves. Is the process exothermic or endothermic? (b) Determine H on a molar basis for CaCl2(s)H2OCa2+(aq)+2Cl(aq)

When one mol of KOH is neutralized by sulfuric acid, q=56 kJ. (This is called the heat of neutralization.) At 23.7C, 25.0 mL of 0.475 M H2SO4 is neutralized by 0.613 M KOH in a coffee-cup calorimeter. Assume that the specific heat of all solutions is 4.18J/gC, that the density of all solutions is 1.00 g/mL, and that volumes are additive. (a) How many mL of KOH is required to neutralize H2SO4? (b) What is the final temperature of the solution?

Indicate which state function is equal to heat, q, for each process described. a. The ignition of a sample in a bomb calorimeter, an unyielding, heavy metal chamberin which samples are burned for heat content analysis b.The melting of an icecube in a cup c.The cooling down ofthe inside of arefrigerator d.A fire in a fireplace

Would the amount of heat absorbed by the dissolution in Example 5.6 appear greater, lesser, or remain the same if the heat capacity of the calorimeter were taken into account? Explain your answer.

When steam condenses to liquid water, 2.26 kJ of heat is released per gram. The heat from 168 g of steam is used to heat a room containing 6.44 104 g of air (20 ft 12 ft 8 ft). The specific heat of air at normal pressure is 1.015 J/(gC). What is the change in air temperature, assuming the heat from the steam is all absorbed by air?

9.102 A runner generates 418 kJ of energy per kilometer from the cellular oxidation of food. The runner's body must dissipate this heat or the body will overheat. Suppose that sweat evaporation is the only important cooling mechanism. If you estimate the enthalpy of evaporation of water as 44 kJ/mol and assume that sweat can he treated as water, describe how you would estimate the volume of sweat that would have to be evaporated if the runner runs a 10-km race.